AceShowbiz - James Cameron has warned "Avatar" fans it may be another four years before they see the next part of the planned sci-fi trilogy - because he's still writing "tons of notes" to develop the sequel. The "Titanic" director began drafting the alien-human love story in 1994 - 15 years before it hit the big screen in December 2009 and shattered worldwide box office records.

Fans are already clamoring to find out what's next for Sam Worthington's character, Jake Sully, and his Na'vi lover Neytiri, played by Zoe Saldana, but, according to the New York Post, he isn't planning to release the first Avatar sequel until 2014. Cameron tells the publication, "Right now, the thinking is that (films) two and three are going to be done together. They'll be released separately, probably a year apart or maybe even two, but they'll be done in a bunch."

"I'm mapping out the story line right now, so there's a proper arc that plays out over two films, but (it) buttons nicely at the end of two, so you don't get this horrible second-act Matrix feeling - you know: 'I've just sat through a three-hour movie and f**k all happened at the end!' "

"Avatar" has so far earned $2.7 billion in box office revenue worldwide, a figure which is expected to skyrocket when the film is re-released for a limited-run on Friday, August 27, featuring eight minutes of never-before-seen footage.